You're friends with a psychic medium who you think can communicate with our dead relatives, and you think seeing some moving light in your room is evidence of this (it's not; it's called the "autokinetic effect
Autokinesis, sometimes called autokinetic effect
, is perceived movement exhibited by a static dim light when it is stared at in the dark.
For example, Sherif's (1937) studies of the autokinetic effect
examined the emergence of group norms in an ambiguous situation.